Oncologists are interested in knowing if the prescribed cancer therapy is having the intended effect, but the tools available to them today to assess a tumor's response to treatment are not very helpful. Palpating the tumor is easy and inexpensive, but it is limited to tumors close to the surface, relies on a physician's memory and notes, and primarily measures size, a trailing indicator of therapy effectiveness. Size reduction only occurs after therapy kills tumor cells and the body's natural processes eliminate the dead cells. Imaging tools (CT, MRI, x-ray) are precise for tumors both close to the surface and in deep tissue, but again primarily measure size, a trailing indicator. Molecular imaging (PET/CT scan) measures both leading and trailing indicators (i.e., metabolism or proliferation, and size) of tumors by capturing positrons emitted from injected radioactive tracers. PET/CT scans are routinely used for pre-therapy staging of cancer. Comparisons of the semi-quantitative Standardized Uptake Values (SUVs) derived from baseline and follow-up PET/CT scans are currently the best available indicator for therapy effectiveness. However, due to the high cost of PET/CT scans, payers limit reimbursement to just a pre-therapy staging scan, except for lymphoma patients. So, oncologists today are left with no timely, cost-effective, and fast way to evaluate the therapy they deliver.
Attempts have been made to image the uptake of radio-labeled tracers using a Positron Emission Tomographic (PET) machine where a small portion of the body is imaged repeatedly. This approach is known as Dynamic PET, and is too slow and costly to be of widespread clinical adoption.
In light of the problems associated with current tumor measurement and prediction systems, it is an object of the present invention to provide an easier, less costly, and more efficient system and method for measuring and predicting the status and/or changes in biological processes.